1. Field of the Invention
The present invention relates generally to surgical devices, and more particularly, to a surgical device for clamping, ligating, and severing tissue, preferably, a side branch of a vessel to be harvested.
2. Prior Art
Both saphenous veins and radial arteries are used as conduits in coronary artery bypass surgery. Conventional techniques for harvesting these vessels involve an incision length approximately equal to the length of the vessel being harvested. Recently, various bipolar endoscopic vessel-harvesting devices have been developed as a means of removing saphenous veins or radial arteries in a minimally invasive manner.
Users of theses devices frequently struggle to separate side branches of the veins or arteries when said side branches run beneath or above the main trunk of the vessel. In addition, the visualization of the vessel may be lost in excess adipose tissue. Finally, the user friendliness of these devices is subject to question since the steps involved in identifying, securing, and dissection/ligation of side branches is not always intuitive, i.e., the user frequently has to concentrate on what his or her hands are doing and not the vessel at hand. Current bipolar devices also fail to complete the terminal ligation required to excise the vein or artery.
Others have attempted to harvest vessels via endoscopic means by several methods. One method involves use of scissors and ligating clips. Two tools are required for this approach, thus complicating the procedure by excess tool exchanges. Furthermore, the placed clips can hinder subsequent movement of instruments. Finally, foreign bodies (clips) are left in the patient""s limb.
Another approach involves the use of a knife placed between two wire guides that are capable of applying a current across the side branch. This design can potentially result in the spread of thermal energy to the target vessel, potentially compromising its utility as a conduit for CABG surgery. Still yet another approach involves the use of scissor-like clamping jaws that open around a side branch, and then must be closed, whereby a current is applied to the vessel within the jaws before the vessel is harvested. However, these types of instruments are difficult to use in confined spaces because of the upward opening movement of at least one of the jaws often causes an interference with objects in the field. Further, the upward opening jaw obscures the vision of the surgeon using the device.
Therefore it is an object of the present invention to provide a surgical device for clamping, ligating, and severing tissue, which is friendlier to use than the devices of the prior art.
It is another object of the present invention to provide a surgical device for clamping, ligating, and severing tissue, which eliminates the need for ligating clips to ligate side branches of a vessel being harvested.
It is yet another object of the present invention to provide a surgical device for clamping, ligating, and severing tissue which limits the spread of thermal energy so as not to compromise the utility of the vessel to be harvested.
It is yet another object of the present invention to provide a surgical device for clamping, ligating, and severing tissue which eliminates the necessity of opening and closing scissor-like jaws.
It is still yet another object of the present invention to provide a surgical device for clamping, ligating, and severing tissue, which minimizes the need for multiple instrument exchanges needed to harvest a vessel.
Accordingly, a surgical device for severing tissue is provided. The surgical device comprising; a first shaft having a first internal lumen and a first slot disposed at a distal end; a clamp slidingly disposed in the first slot between open and closed positions to capture tissue in the first slot, the clamp having a clamping surface disposed at a distal end; at least one electrode for applying RF energy to the tissue captured in the first slot; a cutting blade slidingly disposed in the first slot between open and closed positions, the cutting blade having a cutting edge to sever the tissue; first actuation means for actuating the clamp between the open and closed positions; and second actuation means for actuating the cutting blade between the open and closed positions. The tissue is preferably a side branch of a vessel being harvested. Preferably, the first shaft is disposed at a proximal end to a handle.
The surgical device preferably further comprising a dissection tip disposed at the distal end of the first shaft for dissecting tissue.
The clamp preferably comprises a second shaft having a second internal lumen, the second shaft being slidingly disposed in the first lumen. More preferably, the second shaft has a second slot at the distal end, wherein the second slot divides the clamping surface into two prongs. The cutting blade is preferably slidingly disposed in the second internal lumen of the second shaft. Preferably, the at least one electrode comprises first and second electrodes, each of a different polarity. More preferably, the first electrode comprises at least the clamping surface of the clamp and the second electrode comprises at least the cutting edge of the cutting blade. Alternatively, the first electrode comprises at least the clamping surface of the clamp and at least the cutting edge of the cutting blade and the second electrode comprises at least a portion of the first shaft. The at least a portion of the first shaft preferably comprises an edge defining the first slot in the first shaft.
Preferably, the first actuation means comprises a button movably disposed in a handle and operatively connected to the clamp, wherein moving the button moves the clamp between the open and closed positions. The second actuation means preferably comprises a button movably disposed in a handle and operatively connected to the cutting blade, wherein moving the button moves the cutting blade between the open and closed positions. More preferably, the first and second actuation means comprises a button movably disposed in a handle and operatively connected to the clamp and cutting blade, wherein moving the button a first predetermined amount moves the clamp between the open and closed positions and moving the button a second predetermined amount further moves the cutting blade between the open and closed positions.
Also provided is a method for severing tissue with the surgical devices of the present invention. The method comprising: capturing tissue in the first slot; sliding the clamp in the first slot to clamp the tissue in the first slot; applying RF energy to the at least one electrode to cauterize the tissue; sliding the cutting blade in the first slot to sever the cauterized tissue. The tissue is preferably a side branch of a vessel to be harvested.
The method preferably further comprising dissecting tissue from the vessel to be harvested. Preferably, the first actuation means comprises a button movably disposed in a handle and operatively connected to the clamp, the method further comprising moving the button to move the clamp between the open and closed positions. Preferably, the second actuation means comprises a button movably disposed in a handle and operatively connected to the cutting blade, the method further comprising moving the button to move the cutting blade between the open and closed positions. More preferably, the first and second actuation means comprises a button movably disposed in a handle and operatively connected to the clamp and cutting blade, the method further comprising moving the button a first predetermined amount to move the clamp between the open and closed positions and moving the button a second predetermined amount to further move the cutting blade between the open and closed positions.